The present invention relates to a car security system, and more particularly to a car security system composed of simple circuits, capable of identifying complex signals and detecting unauthorized opening of a car door.
Various conventional car security systems are commercially available at different prices. These security systems are designed with different structures and functions. The mechanical types of car security devices are the most popular ones, such as steering wheel lock, shift lever locks, etc. With respect to electronic car security systems, various expensive detectors are used, such as infrared detector, ultrasonic wave detector, etc. In addition, some of the car security systems are vibration types of security system, including both electronic and mechanical elements. Such a security system is relatively low priced. However, false alarms frequently occur when such security systems are used. Therefore, such security systems are not practical. In addition, when installing the electronic security system, the intrusion or motion detector thereof must be mounted at a suitable position which is often spaced a certain distance from a controller of the security system. Therefore, the detector must be connected to the controller by wiring running some distance through the car. This complicates the installation of the security system and makes the system liable to be interfered with and cause a false alarm.
Therefore, it is necessary to provide a car security system which will eliminate the above shortcomings existing in conventional car security systems.